1. Field
An aspect of the present invention relates to a secondary battery.
2. Description of the Related Art
As industries of electronics, communications, and the like are rapidly developed, the spread of portable electronic devices such as a camcorder, a cellular phone, and a notebook PC has recently been increased. Accordingly, the use of secondary batteries has also been increased. The secondary batteries can be used not only for portable electronic devices but also medium- and large-sized apparatuses such as, for example, an electric tool, an automobile, a space transportation means, a motorbike, a motor scooter, and an aerial transportation means, which require high output and high power. The secondary batteries used for the medium- and large-sized apparatuses may utilize a large-capacity battery module or battery pack by connecting a plurality of battery cells in series or parallel.
Because the secondary battery used for the medium- and large-sized apparatuses uses a plurality of battery cells, heat is not readily emitted to the outside of the secondary battery due to a large amount of current. Therefore, the secondary battery may explode or combust due to the heat. Accordingly, various studies have been conducted to prevent or reduce the chance of explosion and/or fire of a battery by reducing the speed of a large quantity of lithium ions and electrons moving from a negative electrode toward a positive electrode of the battery due to an internal short circuit of the battery.